1. Field of the Invention
The present invention relates to a recording/reproducing apparatus, a video data recording apparatus, a recording method and a reproducing method, capable of receiving digital broadcast for its recording/reproduction.
2. Description of the Related Art
In recent years, digital broadcast, conducting transmission and reception in a digital mode, has taken place, and tape devices such as D-VHS (Digital Tape Recorder) has been developed as apparatus for recording a digital broadcast signal in the form of a bit stream.
FIG. 1 is a block diagram showing a technique related to such a recording/reproducing apparatus.
A digital broadcast signal is inputted to an input terminal 1. The digital broadcasting employs the MPEG2 system. This MPEG2 is designed to send transmission data in units of packets in order to facilitate time division multiplexing of pluralities of images, voices, data and others. One packet is composed of the same type of data, and an identification signal representative of the type of data is added to each packet. According to the MPEG standard, a signal is made to be transmitted through the use of a transport stream (TS) in which a 188-byte length transport packet (TS packet) is taken as a unit of transmission.
Furthermore, each stream, such as video (image) data and audio (voice) data, is sent by an elementary stream (ES). A header is added to the ES to constitute a PES (Packetized Elementary Stream) packet. Since the PES packet is relatively large in volume, its transmission is made with a payload of a plurality of transport packets. Incidentally, a detailed description of the PES appears in ISO/IEC13818-3.
This transport stream comes in the input terminal 1. In recording, the transport stream inputted to the input terminal 1 is supplied to a tape recording device 6 to be recorded on a bit stream recording tape 7.
The transport stream inputted to the input terminal 1 is also given to a selecting circuit 2. This selecting circuit 2 selects the transport stream from the input terminal 1 or the transport stream reproduced from the tape recording device 6 and outputs the selected transport stream to a TS depacket processing section 3.
A demultiplex processing section 4 of the TS depacket processing section 3 demultiplexes the inputted transport stream to separately supply different types of packets on the same program to a PES producing section 5. The PES producing section 5 provides a video PES packet and an audio PES packet by the payload of a plurality of TS packets. These video and audio PES data are forwarded to a video decoder 8 and an audio decoder 9, respectively.
The video decoder 8 decodes video PES data to produce a video signal, while the voice decoder 9 decodes audio PES data to create an audio signal. These video and audio signals are outputted through terminals 10 and 11, respectively.
In this way, in the example of FIG. 1, the inputted transport stream is recorded directly. Thus, the record medium requires a relatively large recording capacity; consequently, a tape medium is generally used as the record medium. However, the use of the tape medium needs a long time for tape supply in the case of jumping reproducing positions and, for example, a problem occurs in that difficulty is experienced in conducting time shift reproduction.
As described above, in the related technique to a recording/reproducing apparatus, when a large-capacity tape medium is employed as a record medium in consideration of a recording capacity, there is a problem in needing a long time for the tape supply in the time shift reproduction or the like.
Accordingly, it is an object of the present invention to provide a recording/reproducing apparatus, a video data recording apparatus, a recording method and a reproducing method, capable of access suitable for a disk medium.
Another object of this invention is to provide a recording/reproducing apparatus, a video data recording apparatus, a recording method and a reproducing method, capable of setting an accurate shift time in time shift reproduction through the use of a disk medium.
A further object of this invention is to provide a recording/reproducing apparatus, a video data recording apparatus, a recording method and a reproducing method, capable of improving the access in the time shift reproduction and the return speed for the ordinary reproduction.
A still further object of this invention is to a recording/reproducing apparatus, a video data recording apparatus, a recording method and a reproducing method, capable of gaining access to specific video data with high efficiency at N-times speed reproduction of a disk retaining compressed and encoded video data.
In accordance with this invention, there is provided a recording and reproducing apparatus comprising reproduction unit detecting means for receiving a compressed and encoded signal to detect a head of a reproduction unit of this signal, recording and reproducing means for recording the compressed and encoded signal on a predetermined record medium and further for reproducing the recorded signal, management information recording means for recording time information corresponding to the reproduction unit head and information on a signal quantity of the reproduction unit, and reproduction control means for making a decision on a reproduction position of the predetermined record medium in reproduction on the basis of the time information and the signal quantity information recorded by the management information recording means.
Furthermore, according to this invention, there is provided a video data recording apparatus which records video data on a disk in a state where the video data is divided in access units of the disk, comprising recording means for conducting the recording in a state where an index for access to an access unit where specific video data is recorded is added to each of the access units.
Still furthermore, according to this invention, there is provided a video data recording method of recording video data on a disk in a state where the video data is divided into access units of the disk, comprising a step of conducting the recording in a state where an index for access to an access unit, where specific video data is recorded, is given to each of the access units.
Moreover, according to this invention, there is provided a video data reproducing method which reproduces video data at an N-times speed from a disk on which the video data is recorded in a state of being divided into access units and an index for access to the access unit where a specific video data exists is recorded in each of the access units, comprising the steps of reading out the index from the disk every predetermined number of access units set on the basis of a multiplier by which the reproduction speed increases accordingly, whenever the index is read out, detecting a recorded position of the access unit where the specific video data exists in accordance with the read index, and reading out recorded data from the access unit at the detected position.
The other features and advantages of the present invention will become more readily apparent from the following description.